If you are using E71 (or other E and N Series’ devices) you may encounter issue with identifying MACs (hardware addresses) for built-in WLAN and Bluetooth modules. Don’t worry! It’s very simple. If you want to connect your phone with your wireless router and it uses MAC filtering try these codes following with green button.
*#62209526# (for WLAN MAC)
*#2820# (for Bluetooth MAC)